Expand description
§Error management
Errors are designed with multiple needs in mind:
- Accumulate more context as the error goes up the parser chain
- Distinguish between recoverable errors, unrecoverable errors, and more data is needed
- Have a very low overhead, as errors are often discarded by the calling parser (examples:
repeat,alt) - Can be modified according to the user’s needs, because some languages need a lot more information
- Help thread-through the stream
To abstract these needs away from the user, generally winnow parsers use the ModalResult
alias, rather than Result. Parser::parse is a top-level operation
that can help convert to a Result for integrating with your application’s error reporting.
Error types include:
EmptyErrorwhen the reason for failure doesn’t matterContextErrorInputError(mostly for testing)TreeError(mostly for testing)- Custom errors
Structs§
- Context
Error - Accumulate context while backtracking errors
- Empty
Error - Track an error occurred without any other
StrContext - Input
Error - Capture input on error
- Parse
Error - See
Parser::parse - Tree
Error Base std - See
TreeErrorFrame::Kind,ParserError::append - Tree
Error Context std - See
TreeErrorFrame::Context,AddContext::add_context
Enums§
- ErrMode
- Add parse error state to
ParserErrors - Needed
- Contains information on needed data if a parser returned
Incomplete - StrContext
- Additional parse context for
ContextErroradded viaParser::context - StrContext
Value - See
StrContext - Tree
Error std - Trace all error paths, particularly for tests
- Tree
Error Frame std - See
TreeError::Stack
Traits§
- AddContext
- Used by
Parser::contextto add custom data to error while backtracking - Error
Convert - Equivalent of
Fromimplementation to avoid orphan rules in bits parsers - From
External Error - Create a new error with an external error, from
std::str::FromStr - From
Recoverable Error unstable-recoverandstd - Capture context from when an error was recovered
- Modal
Error - Manipulate the how parsers respond to this error
- Parser
Error - The basic
Parsertrait for errors
Type Aliases§
- Modal
Result - Modal error reporting for
Parser::parse_next - Result
- By default, the error type (
E) isContextError.